Ventricular septal rupture (VSR) after acute myocardial infarction (MI) is a rare yet fatal complication. Although surgical repair is essential, the optimal timing remains controversial. We report a case of ST-Elevation Myocardial Infarction (STEMI) complicated by VSR. Fibrinolytic therapy was initially considered successful; however, the patient developed worsening dyspnoea. Further evaluation confirmed an apical VSR by echocardiography. The patient received intensive monitoring and supported with an Intra-Aortic Balloon Pump (IABP). Surgical repair was performed on day 26. Hemodynamic initially improved postoperatively, but the condition deteriorated again on the ninth day after surgery, and the patient ultimately died. This case underscores that while surgical repair is the preferred definitive treatment for VSR, the timing of intervention is critical. Proper timing requires balancing surgical risks with tissue readiness and hemodynamic stability. The interval between VSR detection and surgical repair plays a pivotal role in determining patient survival.